The present invention relates to a method of preparing alkali metal hydrides and nitrides by means of easily accessible, new alkali metal complex compounds as well as said new alkali metal complex compounds and their preparation.
Alkali metal hydrides, such as for example lithium hydride or sodium hydride, are formed, as it is known, from the elements lithium and hydrogen at temperatures above 300.degree. C., and especially at temperatures around 700.degree. C. (Kirk-Othmer 1967, Vol. 12, p. 544; Ullmann, Vol. 8, 1957, p. 723). At room temperature, hydrogen does not react with lithium, and is not absorbed by metal no matter how finely divided (E. Wiberg and E. Amberger, "Hydrides of the Elements of Main Groups I-IV", Elsevier Publishing Co., 1971, p. 19).
In the presence of catalysts such as tungsten (IV) or molybdenum (IV) sulfide, the temperature for the preparation of lithium hydride, for example, can be reduced to 310 .degree. to 345.degree. C., and in the presence of lithium stearate as catalyst, it can be reduced to from 240.degree. to 330.degree. C. For the preparation of sodium hydride, catalysts of sodium stearate are used. At a temperature of less than 200.degree. C., it has not been possible to prepare lithium hydride to date. The lowest temperature yet given for the preparation of potassium hydride is 140.degree. C. (Methodicum Chim., Vol. 7, pp. 10-12).
The preparation of lithium nitride at temperatures lower than 350.degree. C., even under the influence of catalysts, has never been described. Temperatures between 500.degree. and 800.degree. C. are preferred (op. cit., p. 60).